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Non-invasive assessment of electrophysiological effects of histamine infusion in man
Insights
Histamine (H) infusions in healthy volunteers caused dose-dependent increases in heart rate and significant ST-T complex depression. High Resolution ECG (H.R.ECG) revealed atrial activity changes, with effects resolving post-infusion.
Area of Science:
- Cardiology
- Electrophysiology
- Pharmacology
Background:
- Histamine is a biogenic amine with known cardiovascular effects.
- Understanding histamine's precise impact on cardiac electrophysiology is crucial for clinical applications.
Purpose of the Study:
- To investigate the electrophysiological effects of sequential intravenous histamine infusions in normal volunteers.
- To assess changes using conventional Electrocardiography (ECG) and High Resolution ECG (H.R.ECG).
Main Methods:
- Five healthy volunteers received two 10-minute intravenous infusions of histamine (0.4 mcg/kg/min and 1.0 mcg/kg/min) with a 60-minute recovery period.
- Conventional ECG and H.R.ECG were used to record cardiac electrical activity.
- Data analysis focused on heart rate, QRS duration, ST-T complex, STJ point, and atrial activity.
Main Results:
- Histamine induced a dose-dependent increase in heart rate.
- Significant depression of the ST-T complex and STJ point was observed.
- H.R.ECG demonstrated notable alterations in atrial activity morphology and voltage.
- QRS complex duration remained unchanged.
Conclusions:
- Histamine administration causes significant, reversible electrophysiological changes in the human heart.
- These effects include altered heart rate, myocardial repolarization, and atrial electrical activity.
- H.R.ECG provides valuable non-invasive insights into histamine-induced cardiac electrophysiological modifications.
Abstract:
The electrophysiological changes induced by sequential infusion of histamine (H) (0.4 and 1.0 mcg/kg/min for 10 min each) were investigated by conventional ECG and High Resolution ECG (H.R.ECG). The latter permits external non-invasive recording of the potentials generated in the cardiac conduction system. H was infused i.v. in 5 normal volunteers with a mean age of 30 years. H infusions were begun with 0.4 mcg/kg/min and continued for 10 min. After a 60 min recovery period a second 10 min infusion (1 mcg/kg/min) was administered. In man H produced a dose-dependent increase in heart rate, a significant depression of the ST-T complex, and a depression in STJ point. The QRS complex duration was unmodified. H.R.ECG showed significant changes in the morphology and voltage of the atrial activity. The electrophysiological effects disappeared within a few minutes after discontinuing the infusions of H.